Arc type continuous casting plant

ABSTRACT

An arc type continuous casting plant for curved strands is comprised of adjustably positionable forming rolls and a straightening machine. The straightening machine is formed of a flexibly mounted holddown roll for applying variable pressure to the strands during the straightening operation, and preferably, includes a counter roll disposed on the opposite side of the cast strand from the holddown roll. A hydraulic piston assembly may be used to mount the holddown roll for variable pressure operation. Further, the counter roll may be interconnected with and movable relative to the holddown roll for handling strands of different thickness. In an embodiment with the strand oriented horizontally the holddown roll is positioned between two pairs of forming rolls while in an arrangement with the strand positioned vertically, the forming rolls are disposed between spaced holddown or straightening rolls.

United States Patent [72] Inventors Curt Herrmann Kiel'ernweg 8; Hans G. Baumann, Mulheimer Strasse 134, 41 Duisburg, Germany [21 Appl. No. 678,391 [22] Filed Oct. 26, 1967 [45] Patented Feb. 23, 1971 [32] Priority Nov. 10, 1966 [3 3] Germany [31 1 D51505 [54] ARC TYPE CONTINUOUS CASTING PLANT 10 Claims, 2 Drawing Figs.

[52] US. 164/282, 72/161,164/76 [51] Int.Cl. B22d 11/12 [50] Field ofSearch 164/76, 82, 270,273,282,283;72/161, 163,164,165

[56] References Cited UNITED STATES PATENTS 648,091 4/1900 Trotz 164/283X 2,698,467 l/ 1955 Tarquihee et a1 164/283X 3,307,230 3/1967 Goss 164/282X 3,314,115 4/1967 Saunders et a1 164/282 3,344,637 10/1967 Polakowski 72/164X 3,358,358 12/1967 Jenks et al. 164/76 Primary ExaminerJ. Spencer Overholser Assistant ExaminerR. Spencer Annear Att0rneyMcGlew and Toren ABSTRACT: An arc type continuous casting plant for curved strands is comprised of adjustably positionable forming rolls and a straightening machine. The straightening machine is formed of a flexibly mounted holddown roll for applying variable pressure to the strands during the straightening operation, and preferably, includes a counter roll disposed on the opposite side of the cast strand from the holddown roll. A hydraulic piston assembly may be used to mount the holddown roll for variable pressure operation. Further, the counter roll may be interconnected with and movable relative to the holddown roll for handling strands of different thickness. In an embodiment with the strand oriented horizontally the holddown roll is positioned between two pairs of forming rolls while in an arrangement with the strand positioned vertically, the forming rolls are disposed between spaced holddown or straightening rolls.

- PATENTEDFEB23I97I 3565;160

. Inventors cue-r HERE/MANN HANS G.- 8AUMANA/ 1 ARC TYPE CONTINUOUS CASTING PLANT SUMMARY or THE INVENTION The present invention is, directed to an arc type continuous casting plant, especially for casting steel, and more particularly, to an arrangement wherein one or more pairs of adjustably positionable forming rolls are disposed adjacent to a withdrawing and straightening machine. In arc type continuous casting plants, straightening machines. have been employed to straighten the casting or strand,- usually a bar shape, after it has been given a curved configuration in the casting operation. Although the shell of the casting has a certain thickness at the place where it is straightened, it is possible, without any major cracks or ruptures in the strand, to bring about-the required change in direction.

However, if instead of a straightening machine, a device using rolls is employed for bringing about a deformation or a reduction in the cross section of the casting, then quite a differe'nt conditionexists. With the change in the shape of the strand an increasing length of the path of travel of the casting is developed and it tends to retain its curved form because of the increasing cooling time which is provided. This tendency of the casting to cool and retain its curved form is also due, in part, to the fact that the forming rolls must be made adjustable to permit the leading end of the strand to extend through them at the beginning of the casting operation. As the strand passes 7 through the forming rolls, it experiences a change in form relative to its cross section. However, it does not change its curved form as it would if it had beenpassed through a straightening machine. 1

If the forming rolls are arranged adjacent to the device where the curved strand is straightened, problems, which have not previously been appreciated, could develop and lead to cracks and even fractures in the casting which would result in the interruption of the entire operation. Where such interruptions occur, the product of the operation is useless and serious economic losses result.

Because of the arrangement of the deforming rolls, whether the casting is oriented horizontally or vertically, there results an arching of the strand which causes the cast member to retain its curved shape. At the commencement of the casting operation, the leading end of the strand must be passed through the first pair of rollers since any deformation at the end of the strip may result in the complete destruction of the casting. In such plants, the strand is not guided into the straightening machine so that it is not possible to obtain a usable product.

Accordingly, one of the primary objects of the present invention isto overcome this drawback in initiating the deforming and straightening operation and, in particular, to prevent any arching of the strand after its passage between the first forming rollers to prevent any arching-of the strand after its passage between the first forming rollers to prevent the tendency of the strand to retain its curved form which is imposed upon it by the supporting rolls. I

Therefore, in the present inventionthis problem is avoided by providing one or more holddown rolls in the vicinity of the rolls forming the strand. The holddown rolls are provided against the upper side of the strand when the strand is arranged horizontally, and are flexible within certain limits in the estent to which pressure can be applied to the strand. This arrangement is not merely intended to support the strand as it is being deformed, but rather, in accordance with the conditions of the strand passing through the rolls to press the strand uniformly against the base of the holddown or straightening device whereby the strand is reoriented into a straight line and any arching stresses which existed within the strand are eliminated.

Accordingly, the present invention has the advantage of straightening the strand immediately after the deforming operation while it is in a state where this can be done. It has the further advantage of eliminating, at least to a degree, the

inherent stresses which are developed in the strand.

In one embodiment of the invention, where the rolls are mounted in a vertically arranged frame, it is preferred to dispose the holddown rolls between a spaced pair of forming rolls in the frame. Such an arrangement has the advantage of providing an almost equilateral change in form and direction of the cross section of thestrand and of its axis.

On the other hand, if the frame supporting the rolls is disposed horizontally, it has been found advantageous to dispose the hold down rolls on either side of the forming rolls. In this arrangement, the deformation of the strand takes place between two points of support for the strip and, as a result, not only may a precise pass through the forming rolls be achieved, but also in this combination a complete change in the orientation of the strand from a curved to a straight line disposition is obtained.

Based on the given conditions of the dimension of the strand and the data of the continuous casting operation, it is possible to determine the specific transition point for locating the holddown roll for changing the shape of the strand from curved to straight. In such a setup the deforming means can be positioned either in front of or behind the point at which the strand is straightened.

Moreover, in accordance with the invention, the holddown rolls may be flexibly supported by means of hydraulic pressure regulation equipment. In this arrangement, a smaller or greater force can be exerted on the strand depending on the particular conditions of the strand as it passes through the straightening device.

.Another feature of the invention is that the holddown roll need not have the profile or shape of the cast member such as is required of a deforming or reducing roll, because, at the point where the holddown roll is positioned, the strand does not experience any deformation, or the deformation is of a relatively small amount in comparison to that provided by the defonning rolls. Toassure the proper application of pressure, by means of the holddown roll, a hydraulic device is particularly suitable because it provides a range of pressure forces and also permits fine adjustment of the application of pressure to the holddown roll. v

Still, another feature of the invention is that the flexible support for the holddown roll may be provided by a pressure spring support with a steep curve in its force displacement characteristic. In simple arrangements such a support device can effectively provide a flexible influence on the strand.

In the straightening operation, in addition to the holddown roll one or a number of counter rolls may be positioned on an opposite side of the strand from the holddown roll. The counter roll is preferably associated with the holddown roll in such a manner that the counter roll is movable relative to the holddown roll permitting a variation in the dimension of the strands which may be passed between them. The feature of varying the spacing between the holddown and counter rolls is of particular importance because the casting passing from the forming rolls to the straightening device may be of varying dimensions. Additionally, this variable arrangement of the rolls has a further advantage in guiding the leading end of the strand at the beginning of the casting operation since it is cooled off to a greater degree than the portion which follows it. At the beginning of the casting operation as the forming rolls are adjusted the holddown and counter rolls are able to follow the changes in the dimensions of the strand as it is fed into the straightening device.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated and described a preferred embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a vertical sectional view of a diagrammatic arrangement of an arc type continuous casting plant with the casting being passed between the forming and straightening means; and

FIG. 2 is a partial view of the arrangement shown in FIG. 1 illustrating another embodiment of the straightening means.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawing, a strand 1 in an arc type continuous casting operation is shown passing through a machine frame 2 which contains two deforming or shaping stations 3 and 4. The deforming station 3 contains a pair of horizontally arranged adjustably positionable rolls 5 and 6 which are located at a relatively short distance from a pair of vertically disposed rolls 7 in the other deforming station 4. Ascan be noted in the drawing, the section lb of the strand 1 as it enters the gap between the rolls 5 and 6 is reduced or compressed in a vertical direction and as it passes between the rolls 7, it is deformed in the horizontal direction providing the deformed strand section la.

Located between the two pairs of rolls 5 and 6, and 7 is a straightening device comprising an upper holddown roll 8 and a lower counter roll 9. The counter roll 9 may be held rigidly in position or, as previously mentioned, it may be adjustable relative to the holddown roll 8 by means of the hydraulic con trol for the holddown roll.

The holddown roll 8 is supported by a fork member 10 secured to the roller bearings of the holddown roll. The fork is, in turn, articulated to the piston rodll which forms a portion of the piston driving mechanism 12. The piston drive mechanism 12 is flexibly mounted on the frame 2 by means of a connection 13.

The arrangement set forth in the drawing operates in the following manner. At the beginning of the continuous casting operation, the leading edge of the strand or casting is passed between the adjustably positionable rolls 5 and 6 which are spaced apart for admitting the leading edge between the holddown roll 8 and its counter roll 9. The rolls 8 and 9 which perform the straightening operation do not cause any appreciable deformation of the cross section of the strand. With the leading edge of the strand guided into the straightening rolls, the forming rolls 5 and 6 are positioned against the strand and the operation is ready to commence. By means of a control system (not shown) the rolls 8 and 9, which may be adjusted either automatically or manually, are now ready to perform the straightening operation on the strand emerging from between the rolls 5 and 6. As the straightened strand passes from the rolls 8 and 9 to the vertically arranged rolls 7, it is almost completely freed from internal stresses caused by its curved orientation prior to entering the rolls 5 and 6. The speed of the continuous casting operation and of the rolling and straightening steps is adjusted relative to one another so that the circumferential speed of the forming rolls takes into account fully the degree of deformation being impressed on the strand. Accordingly, depending on the cross-sectional dimensions of the strand, the section In of the strip emerging from the vertical rolls 7 can have a speed in its path of travel which is a multiple of that of section lb of the strip whichis delivered into the horizontally arranged rolls 5 and 6. In FIG. 2, in place of the piston drive mechanism 12, a pressure spring support 14 with a steep curve in its force displacement characteristic provides a flexible support for the roll 8. Y

The driving mechanism for the horizontally and vertically arranged rolls 5 and 6 and 7 may be located either below the level of the casting room floor 14 or mounted on the side of the frame 2.

While the holddown roll 8 and the counter roll 9 perform the'straightening operation by themselves it is possible that they may be supported in this operation by the deforming rolls. The tendency of the curved strand to arch in one direction or another is primarily a function of the manner in which the roll dimensions in the deforming stations 3 and 4 are arranged. For example, by means of a smaller lower roll in the deforming station 3, the downward pressure or force of the holddown roll 8 can be supported whereby with a pinion means and a smaller circumferential speed of the lower roll a larger frictional force can be transmitted to the under side of the strand when it is desired to provide a greater downward force on the casting. Accordingly, the holddown and counter rolls not only effectively straighten the strand but also, in combination with one or both of the deforming stations, can influence the internal stresses of the strand. it is also within the scope of the invention in the event that several holddown rolls are employed to provide counter rolls on either the upper or lower side of the strand in a staggered arrangement.

While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

We claim:

1. A device for use in an arc type continuous casting plant in which curved strands are cast, for straightening the strands and preventing arching stresses caused by deformation of the strand, comprising at least one pair of adjustably positionable deforming rolls arranged to receive the strand therebetween and to deform the strand as it passes through said rolls, and at least one holddown roll located adjacent said pair of defonning rolls, and means in combination with said holddown roll for contacting and exerting pressure against one surface of the strand and for varying the pressure applied to the surface of the strand so that said holddown roll acts to prevent arching of the deformed strand.

2. A device, as set forth in claim 1, wherein said holddown roll is located above the upper surface of the strand which is oriented horizontally for its passage through said deforming rolls and under said holddown roll.

3. A device, as set forth in claim 2, wherein a counter roll is disposed below and opposite the holddown roll for contact with the underside of the strand.

4. A device, as set forth in claim 2, wherein a hydraulically operated mechanism is arranged in operative engagement with said holddown roll for varying the pressure exerted by said holddown roll on the strand.

5. A device, as set forth in claim 2, wherein a pressure spring support having a steep curve of its forced displacement characteristic is arranged to support said holddown roll.

6. A device, as set forth in claim 4, wherein said hydraulically operated mechanism comprises a piston cylinder located above said holddown roll, a piston rod extending downwardly from said piston cylinder, and a fork member secured to said piston rod and to said holddown roll.

7. A device, as set forth in claim 2, wherein two pair of said deforming rolls are provided with one pair of said rolls located on one side of said holddown roll and the other pair of said rolls is located on the opposite side of said holddown roll so that the strand passes first through a pair of said deforming rolls then under said holddown roll and then through the other said pair of deforming rolls.

8. A device, as set forth in claim 7, wherein one pair of said defonning rolls having their axes disposed horizontally for deforming the strand in the vertical direction and the other said pair of deforming rolls having their axes arranged vertically for deforming the strand in the horizontal direction.

9. A device, as set forth in claim 3, wherein a horizontally disposed machine frame, a pair of said deforming rolls mounted on said machine frame, a pair of said holddown roll and counter roll located on each side of said deforming rolls so that the strand passes first between one of said holddown rolls and counter rolls then through said deforming rolls and then through the other holddown roll and counter roll.

10. A device for use in an arc type continuous casting plant in which curved strands are cast, for straightening the strands, comprising at least one pair of adjustably positionable deforming rolls arranged to receive the strand therebetween and to deform the strand as it passes through said rolls, and at least one holddown roll located adjacent said pair of deforming rolls, means in combination'with said holddown roll for contacting and exerting pressure against one surface of the strand and for varying the pressure applied to said strand so that said holddown roll acts to prevent arching of the deformed strand, said holddown roll located above the upper surface of the strand which is oriented horizontally for its passage through said deforming rolls and under said holddown roll, said means 1 0 from said holddown roll for receiving therebetween strands of varying thickness. 

1. A device for use in an arc type continuous casting plant in which curved strands are cast, for straightening the strands and preventing arching stresses caused by deformation of the strand, comprising at least one pair of adjustably positionable deforming rolls arranged to receive the strand therebetween and to deform the strand as it passes through said rolls, and at least one holddown roll located adjacent said pair of deforming rolls, and means in combination with said holddown roll for contacting and exerting pressure against one surface of the strand and for varying the pressure applied to the surface of the strand so that said holddown roll acts to prevent arching of the deformed strand.
 2. A device, as set forth in claim 1, wherein said holddown roll is located above the upper surface of the strand which is oriented horizontally for its passage through said deforming rolls and under said holddown roll.
 3. A device, as set forth in claim 2, wherein a counter roll is disposed bElow and opposite the holddown roll for contact with the underside of the strand.
 4. A device, as set forth in claim 2, wherein a hydraulically operated mechanism is arranged in operative engagement with said holddown roll for varying the pressure exerted by said holddown roll on the strand.
 5. A device, as set forth in claim 2, wherein a pressure spring support having a steep curve of its forced displacement characteristic is arranged to support said holddown roll.
 6. A device, as set forth in claim 4, wherein said hydraulically operated mechanism comprises a piston cylinder located above said holddown roll, a piston rod extending downwardly from said piston cylinder, and a fork member secured to said piston rod and to said holddown roll.
 7. A device, as set forth in claim 2, wherein two pair of said deforming rolls are provided with one pair of said rolls located on one side of said holddown roll and the other pair of said rolls is located on the opposite side of said holddown roll so that the strand passes first through a pair of said deforming rolls then under said holddown roll and then through the other said pair of deforming rolls.
 8. A device, as set forth in claim 7, wherein one pair of said deforming rolls having their axes disposed horizontally for deforming the strand in the vertical direction and the other said pair of deforming rolls having their axes arranged vertically for deforming the strand in the horizontal direction.
 9. A device, as set forth in claim 3, wherein a horizontally disposed machine frame, a pair of said deforming rolls mounted on said machine frame, a pair of said holddown roll and counter roll located on each side of said deforming rolls so that the strand passes first between one of said holddown rolls and counter rolls then through said deforming rolls and then through the other holddown roll and counter roll.
 10. A device for use in an arc type continuous casting plant in which curved strands are cast, for straightening the strands, comprising at least one pair of adjustably positionable deforming rolls arranged to receive the strand therebetween and to deform the strand as it passes through said rolls, and at least one holddown roll located adjacent said pair of deforming rolls, means in combination with said holddown roll for contacting and exerting pressure against one surface of the strand and for varying the pressure applied to said strand so that said holddown roll acts to prevent arching of the deformed strand, said holddown roll located above the upper surface of the strand which is oriented horizontally for its passage through said deforming rolls and under said holddown roll, said means comprising a hydraulically operated mechanism in operative engagement with said holddown roll for varying the pressure exerted on the strand, and a counter roll disposed opposite said holddown roll in contact with the underside of the strand opposite said holddown roll, said counter roll being movably secured to said holddown roll for movement toward and away from said holddown roll for receiving therebetween strands of varying thickness. 